1. Field of the Invention
This invention relates to a programmable high-speed motor torque controller, and in particular, to a programmable high-speed motor torque controller, which is artfully integrated with a high-speed pulse-width-modulation IC (PWM IC) and the programmable microprocessor (MCU) so as to achieve a quick power-saving, safe and reliable effect.
2. Description of the Prior Art
For the purpose of reducing the electric conversion loss, the present motor controllers are entirely based on the scheme of the pulse-width-modulation (PWM). Normally, there are three possible solutions to implement a robust PWM control scheme, which are the simple PWM IC, the microprocessor (MCU) with PWM generator, and the digital signal processor (DSP). However, the existing technologies or components associated with the PWM application all have some drawbacks or restrictions described as follows.
Firstly, a simple PWM IC is able to provide the basic function of power conversion. With the development of power electronics, its switching frequency is up to 500 KHz. Moreover, the built-in feedback control circuit of the PWM IC is able to provide basic output control of constant voltage or constant current. In addition, some of the PWM ICs even build in the high-voltage gate driver and the input port of the reference signal. However, since the possible supporting functions of such control chip are defined at the chip-designing stage, such simple PWM IC always fails to appropriately meet the specific requirements of the industry applications. For example, there is a set of electronic switch is normally used to cut off the current path for the safety concern of e-bike application if there is no power outputted from the motor. However, it is difficult for the current PWM IC to achieve such simple function. Besides, the PWM ICs with the high-voltage gate driver are not cost-effective.
Secondly, a portion of the current MICROPROCESSOR built-in a PWM generator is able to perform the limited motor control. However, due to the limitation of the computing resource, such MICROPROCESSOR generally fails to perform the real-time control coinciding with the practical state of a high-speed current-variance. Doubtless, the frequency of the entire switching circuit is limited, and its efficiency is disagreeable. In addition, such that the electrical system and the motor are normally noisy and power wasteful as the electrical system is forced to switch within the audio frequency range (<20 KHz).
Thirdly, as regards the digital signal processor (DSP) with the PWM generator, nowadays, only a few manufacturers can provide such specified DSPs for motor controllers. Since they are not widely used, they are still not cost-effective. In addition, for a purpose of rapidly modulating the control statuses, these digital signal processors should be operated at an extremely high speed. In other words, they are not suitable to a low-power control system.
Fourthly, as regards the drag force of the motor upon reverse rotation, as shown in FIG. 1 which illustrates the architecture of an existing motor controller, a free wheeling diode 10 should be provided on both input terminals of the motor 11. In this manner, a relief loop of the inductive current of the motor 11 is offered to prevent other components from breakage due to the inductive voltage. However, when the motor 11 is reversely rotated, the free wheeling diode 10 will be forwardly conducted, thereby imposing a strong braking-drag effect. Such effect is disadvantageous for the electrical bicycle or the motorcycle to drive back.
Accordingly, the above-described prior art product is not a perfect design and has still many disadvantages to be solved.
In views of the above-described disadvantages resulted from the conventional motor torque controller, the applicant keeps on carving unflaggingly to develop a programmable high-speed motor torque controller according to the present invention through wholehearted experience and research.